[Bug]: Revert workaround for webpack lazy compilation bug

Describe the bug

Webpack has now fixed the lazy compilation bug that prompted us to add a workaround in #18432. Confirmed both reproductions are resolved.

In the Storybook repro, the test runner still times out on the first run, but that seems unrelated to the webpack bug (and likely already addressed elsewhere). Since the test runner already warns users about lazy compilation, reverting this workaround shouldn’t make things worse.

We should

• Remove the work
• Verify Storybook still runs correctly with lazy compilation enabled
• Confirm test runner behavior remains consistent

Reproduction link

https://github.com/webpack/webpack/issues/15541

Reproduction steps

No response

System

-

Additional context

No response